This invention relates to a portable electronic memorandum device with a data memory which allows reading/writing of character data items such as names, telephone numbers, addresses, schedules and the like.
Recent commercially available electronic wrist watches, small electronic calculators, etc. are usually provided with time display and calculating functions. Some of these electronic devices additionally have a so-called data bank function. These devices with the data bank function have memories for storing item data such as names, telephone numbers, and schedules. Users can read out desired item data from the memories at any time. More specifically, these electronic devices usually have a secret function for protecting such data from being stolen by other persons. To this end, this device uses passwords, or secret words, without which the item data cannot be read out.
For example, U.S. Pat. No. 4,117,542 discloses two types of data bank electronic device with the so-called secret function. In the first type of the electronic device, a user presets secret codes of his own in a RAM of the device. For reading out desired data later, he enters the secret code associated with that data, which has been preset. In the second data bank electronic device, secret codes have been fixed in the ROM at the factory. The operator uses these fixed secret codes later for his desired data retrieval through appropriate keyboard operation.
However, the second type electronic device, in which secret codes have been stored in the manufacturing stage, has disadvantages. For example, if a user forgets the password, he cannot use the memory area of the device unless he can recall the password or find it out from the maker.
The first type of the electronic device, in which the user himself enters the password data into the RAM, has the following disadvantages. If the user, with a specified device model, sets the password data, for example, by key operation, it is naturally set with the procedure specified for that model. If the model device being operated by the user is one widely marketed in great numbers, the password data setting, cancellation, and change procedures for that model will be known by many people. As a result, even though the password is supposed to be secret, the cancellation and change of the password can be very easily performed by other persons, and there is danger that the secrecy will not be maintained.